CVE-2026-102808 in Autopilot
Summary
by MITRE • 09/29/2026
PX4 Autopilot through 1.17.0 contains a NULL pointer dereference vulnerability in the sd_stress command where the -b byte count parameter is parsed without validation before being passed to malloc() and memset(). Attackers with shell access, including through MAVLink, can supply invalid byte count values to crash the flight controller.
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Analysis
by VulDB Data Team • 09/29/2026
The PX4 Autopilot software, a widely used open-source autopilot system for unmanned aerial vehicles, contains a critical memory management flaw in its command-line interface implementation. Specifically, within version 1.17.0 and earlier releases, the sd_stress utility exhibits improper input validation when processing the byte count parameter designated by the -b flag. This component is designed to perform stress testing on storage devices but fails to verify that the provided integer value represents a valid, non-negative size before proceeding with memory allocation operations. The vulnerability stems from a lack of boundary checks and type safety enforcement during the parsing phase, allowing arbitrary or malformed values to propagate directly into system-level functions responsible for dynamic memory management.
From a technical perspective, this flaw constitutes an improper input validation issue that leads to unsafe memory access patterns. When the sd_stress command receives a byte count argument, it immediately attempts to allocate that amount of memory using malloc and subsequently initialize it with memset. If the attacker supplies a negative integer due to sign extension issues or overflow conditions during parsing, the resulting value passed to these functions may be interpreted as an extremely large unsigned integer by the underlying C library routines. Alternatively, if zero is provided in certain contexts where non-zero allocation was expected, or if other invalid values cause arithmetic errors, the system behavior becomes undefined. In many implementations of such utilities, passing a negative number for size parameters results in malloc returning NULL because it cannot allocate memory with a negative size interpretation that translates to an excessively large unsigned value exceeding available resources, or simply fails validation checks internally leading to null returns without proper error handling upstream.
The operational impact of this vulnerability is severe for the integrity and availability of unmanned aerial vehicle systems running PX4. An attacker who has gained shell access to the flight controller can exploit this flaw by invoking the sd_stress command with a crafted byte count argument. This action triggers the NULL pointer dereference when subsequent code attempts to write data into the memory block returned by malloc, which is null due to allocation failure or invalid parameter handling. The immediate consequence of such an event is a segmentation fault that crashes the process running the sd_stress utility and potentially destabilizes the broader autopilot software stack depending on how signal handlers are configured. For autonomous drones relying on continuous real-time operation, this crash can lead to loss of control, unintended flight maneuvers, or complete system failure during critical phases of mission execution such as takeoff, navigation, or landing.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-476 which describes a NULL pointer dereference condition where software attempts to use a pointer that is null rather than checking for nullity before usage. Furthermore, the attack vector relates to ATT&CK technique T1059 Command and Scripting Interpreter as it involves executing specific commands within the operating environment of the flight controller via shell access or MAVLink command injection. The presence of this flaw highlights risks associated with embedded systems where external interfaces like MAVLink provide direct pathways for interacting with low-level system utilities without sufficient sandboxing or input sanitization layers.
Mitigation strategies must focus on rigorous input validation and defensive programming practices within the PX4 codebase. Developers should implement explicit checks to ensure that all integer parameters passed to memory allocation functions are positive, non-zero, and within reasonable bounds relative to available system memory before invoking malloc or memset. Additionally, error handling routines must be strengthened to gracefully manage cases where memory allocation fails due to invalid inputs rather than proceeding with null pointers. Updating the PX4 Autopilot software to versions newer than 1.17.0 is essential as these updates typically include patches addressing such input validation deficiencies. For operators unable to update immediately, restricting shell access and limiting MAVLink command permissions can reduce the attack surface by preventing unauthorized users from invoking vulnerable utilities like sd_stress.